The case should prompt more communities to develop a comprehensive range of preventive measures and consequences – from encouraging bystanders to come forward to training adults how to respond, experts say.

“Today in American schools, these kind of abusive behaviors between teenagers have become so frequent that many adults look upon them now as normal," says Ms. Englander. "Cases like this cause everybody to step back and say, ‘Wait ... Is this something that really has to happen, or is it something we should be correcting?’ ”

Empowering bystanders to speak up

Phoebe was reportedly bullied after relationships with two popular boys. The charges against two boys and seven girls range from statutory rape to criminal harassment to civil rights violations resulting in bodily injury. The teens tormented her for nearly three months, primarily in school, although some of it occurred electronically as well, Ms. Scheibel said.

This case could encourage bystanders to confront those who bully fellow students, because it allows them to point to an instance where teens have been arrested for harassment. That is important, because bystanders can play a significant role in bringing about change, says Parry Aftab, executive director of WiredSafety, an online safety nonprofit in Fort Lee, N.J.

“The more kids who have to face the legal system ... the more likely kids will understand that this has consequences,” she says.

But criminal prosecution for serious cases is not enough, says Stan Davis, a guidance counselor and teacher trainer who runs the website stopbullyingnow.com. There also has to be “day after day, smaller consequences for lower-level behavior,” he says.

He notes that 22 percent of students said peers mistreated them at least twice a month, according to a recent survey of more than 2,000 fifth- through 12th-graders that he and a colleague worked on through the Youth Voice Project. Of those students, more than half (54 percent) percent experienced moderate, severe, or very severe trauma.

Forty-two percent told an adult at school, and 58 percent told an adult at home. Of those, 34 percent said reporting it to the adults made things better.

A role for administrators?

Some school districts are basing prevention programs around research on what works, but too many are not, says Miriam Rollin, national director of Fight Crime: Invest in Kids, a coalition of police chiefs, prosecutors, and violence survivors. She hopes this case will be a wakeup call and lead to better federal funding and better training for adults about how to respond to reports of bullying.

The Massachusetts prosecutor has not brought charges against South Hadley High School administrators. But the picture of how much they knew and whether they responded appropriately is still emerging.

A new anti-bullying law is currently working its way through the Massachusetts legislature – sparked in part by the suicides of Phoebe and another student in the state. Among its provisions is a requirement for principals to report bullying to police if they believe it might warrant criminal charges.